This invention relates, in general, to semiconductor devices and more particularly, to an end plug for a shipping rail or carrier used in transporting semiconductor devices.
Typically semiconductor devices are transported in long tubular rails or carriers. The semiconductor devices are inserted through open ends of the tubular rails. In the past, the openings in the ends of the tubular rails were blocked by a pin which was inserted through the top of the rail. More recently with the widespread use of surface mounted devices the ends of the rails have been blocked by the use of a plug which is inserted into the tubular end of the rail. The plug forms a friction fit with the inside walls of the tubular rail so that it does not accidentally fall out. However, a problem arises due to the fact that there can be a buildup of tolerance of the length of the semiconductor devices. Therefore, with the tolerance buildup there may be a space or gap remaining between the end of the plug and the first semiconductor device which is adjacent to the plug. When this occurs the leads of the semiconductor device can become bent due to inertial impact against the plug caused by the semiconductor devices sliding within the rail or carrier. On the other hand, if the tolerance of the semiconductor devices is on the plus side the total length of the devices can encroach upon the space available for the plug and then when the plug is inserted into the tubular rail the leads of the semiconductor devices are damaged just from the insertion of the end plug into the tubular rail.
One attempt at solving the damaged lead problem was to insert a small piece of foam rubber pad into the tube or cavity of the rail and then to provide a vertical pin through the rail in order to retain the foam rubber pad along with the semiconductor devices. Another approach was to use an accordion design to provide a mechanism to compensate for the tolerance buildup problem. The accordion design approach was not very satisfactory due to the accordion portion of the plug folding against a wall of the rail or carrier and locking in place thus preventing the accordion plug from performing its desired function.
Accordingly, it is an object of the present invention to provide an improved end plug for a semiconductor carrier having unitary tolerance compensating means.
Another object of the present invention is to provide a tolerance compensating end plug which eliminates the need for additional packing material in the semiconductor device rail.
A further object of the present invention is to provide a tolerance compensating end plug which provides a cushion for the leads of a semiconductor device during transit in a shipping rail or carrier.